/*
 * Copyright (c) 2008, 2009 Sun Microsystems. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
 * which accompanies this distribution.
 * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * Contributors:
 *     Linda DeMichiel - Java Persistence 2.0 - Version 2.0 (October 1, 2009)
 *     Specification available from http://jcp.org/en/jsr/detail?id=317
 */

// $Id: SecondaryTable.java 20957 2011-06-13 09:58:51Z stliu $

package javax.persistence;

import java.lang.annotation.Retention;
import java.lang.annotation.Target;

import static java.lang.annotation.ElementType.TYPE;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

/**
 * Specifies a secondary table for the annotated entity
 * class. Specifying one or more secondary tables indicates that the
 * data for the entity class is stored across multiple tables.
 *
 * <p> If no <code>SecondaryTable</code> annotation is specified,
 * it is assumed that all persistent fields or properties of the
 * entity are mapped to the primary table. If no primary key join
 * columns are specified, the join columns are assumed to reference
 * the primary key columns of the primary table, and have the same
 * names and types as the referenced primary key columns of the
 * primary table.
 *
 * <pre>
 *    Example 1: Single secondary table with a single primary key column.
 *
 *    &#064;Entity
 *    &#064;Table(name="CUSTOMER")
 *    &#064;SecondaryTable(name="CUST_DETAIL",
 *        pkJoinColumns=&#064;PrimaryKeyJoinColumn(name="CUST_ID"))
 *    public class Customer { ... }
 *
 *
 *    Example 2: Single secondary table with multiple primary key columns.
 *
 *    &#064;Entity
 *    &#064;Table(name="CUSTOMER")
 *    &#064;SecondaryTable(name="CUST_DETAIL",
 *        pkJoinColumns={
 *            &#064;PrimaryKeyJoinColumn(name="CUST_ID"),
 *            &#064;PrimaryKeyJoinColumn(name="CUST_TYPE")})
 *    public class Customer { ... }
 * </pre>
 *
 * @since Java Persistence 1.0
 */
@Target(TYPE)
@Retention(RUNTIME)
public @interface SecondaryTable {
	/**
	 * (Required) The name of the table.
	 */
	String name();

	/**
	 * (Optional) The catalog of the table.
	 * <p> Defaults to the default catalog.
	 */
	String catalog() default "";

	/**
	 * (Optional) The schema of the table.
	 * <p> Defaults to the default schema for user.
	 */
	String schema() default "";

	/**
	 * (Optional) The columns that are used to join with
	 * the primary table.
	 * <p> Defaults to the column(s) of the same name(s)
	 * as the primary key column(s) in the primary table.
	 */
	PrimaryKeyJoinColumn[] pkJoinColumns() default { };

	/**
	 * (Optional) Unique constraints that are to be placed on the
	 * table. These are typically only used if table generation
	 * is in effect. These constraints apply in addition to any
	 * constraints specified by the <code>Column</code> and <code>JoinColumn</code>
	 * annotations and constraints entailed by primary key mappings.
	 * <p> Defaults to no additional constraints.
	 */
	UniqueConstraint[] uniqueConstraints() default { };
}
